Hoist-testing apparatus and control system therefor

ABSTRACT

Apparatus for testing the rated load, speed and braking capabilities of a hoist comprises a hydraulically operated test winch which imposes a predetermined load or line pull at a predetermined speed on the hoist line. The hoist line is connected to the test winch cable by a lever and pulley arrangement. A load cell responsive to lever movement and, therefore, the load imposed, provides a visual readout thereof at an operation control station. Load size is remotely adjustable from the control station by a load control rheostat which controls an electric-hydraulic pressure control valve which, in turn, adjusts the pressure relief setting of a pressure relief valve between a hydraulic winch motor and the hydraulic pump for that motor. A load control pressure gauge at the control station is responsive to output pressure of the electric-hydraulic pressure control valve for the pressure relief valve and is calibrated to indicate pounds of line pull or load which the hoist being tested can exert to enable the operator to set the load control rheostat accordingly. Load speed is remotely adjustable from the control station by a speed control rheostat which controls another electric-hydraulic pressure control valve which, in turn, operates a cylinder to adjust the speed setting of a servo-stem speed control device on the pump. A speed control pressure gauge at the control station is responsive to output pressure of the other electric-hydraulic pressure control valve for the speed adjustment cylinder and is calibrated to indicate feet per minute of hoist line speed to enable the operator to set the speed control rheostat accordingly.

United States Patent 1191 Gordon Mar. 27, 1973 HOIST-TESTING APPARATUSAND CONTROL SYSTEM THEREFOR Richard O. Gordon, Belgium, Wis.

22 Filed: Nov. 3, 1971 21 Appl.No.: 195,114

[75] Inventor:

Primary ExaminerCharles A. Ruehl Attorney.lames E. Nilles [5 7] ABSTRACTApparatus for testing the rated load, speed and braking capabilities ofa hoist comprises a hydraulically operated test winch which imposes apredetermined load or line pull at a predetermined speed on the hoistline. The hoist line is connected to the test winch cable by a lever andpulley arrangement. A load cell responsive to lever movement and,therefore, the load imposed, provides a visual readout thereof at anoperation control station. Load size is remotely adjustable from thecontrol station by a load control rheostat which controls anelectric-hydraulic pressure control valve which, in turn, adjusts thepressure relief setting of a pressure relief valve between a hydraulicwinch motor and the hydraulic pump for that motor. A load controlpressure gauge at the control station is responsive to output pressureof the electric-hydraulic pressure control valve for the pressure reliefvalve and is calibrated to indicate pounds of line pull or load whichthe hoist being tested can exert to enable the operator to set the loadcontrol rheostat accordingly. Load speed is remotely adjustable from thecontrol station by a speed control rheostat which controls anotherelectric-hydraulic pressure control valve which, in turn, operates acylinder to adjust the speed setting of a servo-stem speed controldevice on the pump. A speed control pressure gauge at the controlstation is responsive to output pressure of the other electric-hydraulicpressure control valve for the speed adjustment cylinder and iscalibrated to indicate feet per minute of hoist line speed to enable theoperator to set the speed control rheostat accordingly.

13 Claims, 4 Drawing Figures SHEET 1 BF 2 INVENTOR.

Mimi/v47 PATENTFUHARZYIQTS BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to hoist-testing apparatus, and, inparticular, to control systems therefor.

2. Description of the Prior Art In the manufacture of overhead hoists,for example, it is desirable to test them to determine if they meettheir rated load-handling capacities and rated speeds of operation.Usually, the hoists are tested under static load, running load up, andrunning load down. In one part of the test, the hoist brake is set undermaximum load and then a further load 150 percent of maximum) is imposedon the hoist. Heretofore, a hoist to be tested was suspended over alarge pit and large, heavy steel test weights were attached to the hoistline. As many individual weights were used as was necessary to meet theload rating of the hoist under various test conditions and then thehoist was operated at its rated speed. For example, one size of: hoistmight be rated for a 25,000 pound line pull at 200 feet per minute andanother size might be rated at a 100,000 line pull at 150 feet perminute. Furthermore, since hoist gear effiency for a particular hoistdiffers during hoisting or lowering, more weight was needed to testhoisting capacity than to test lowering capacity. While such testinggave satisfactory results, physically loading and unloading the testweights was difficult, dangerous and might take several hours. In someinstances, therefore, not every hoist was tested, but only a smallpercentage out of a given production run. It is desirable, therefore, toprovide improved hoist-testing apparatus and control systems thereforwhich overcome the aforedescribed disadvantages and have otheradvantages.

SUMMARY OF THE INVENTION Hoist testing apparatus and a control systemtherefor in accordance with the invention is used to test a hoist havinga motor, a drum and a hoist line. The apparatus comprises a test winchhaving a hydraulic motor, a

' drum driven thereby and a test cable. The apparatus ment and provide avisual readout on a gauge at an operation control station of the size ofthe load. The hydraulic winch motor is supplied with pressurized fluidfrom a hydraulic pump driven by an electric motor and having speedadjusting means thereon, such as a servo-stem speed control which ismovable to vary the fluid output from the pump.

Load control means are provided to vary the load imposed on the hoistline so that a maximum load (or some percentage thereof) can be imposedon a particular hoist being tested. Such load control means take theform of a load control rheostat at the control station which controlsfluid pressure from an adjustable electric hydraulic pressure controlvalve to regulate the pressure relief setting of a pilot operatedadjustable pressure relief valve between the pump and the hydraulicwinch motor. A load control pressure gauge at the control station isresponsive to output pressure of the electric-hydraulic pressure controlvalve for the pressure relief valve and is calibrated to indicate poundsof line pull or load which the hoist being tested can exert to enablethe operator to set the load control rheostat accordingly.

Speed control means are provided to vary the speed at which the winchoperates so that it matches the rated speed of the hoist line. Suchspeed control means take the form of a speed control rheostat at thecontrol station which controls fluid pressure from anotherelectric-hydraulic pressure control valve which is used to controlmovement of a piston in a hydraulic cylinder connected to the movableservo-stem speed control on the pump. A speed control pressure gauge atthe con-' trol station is responsive to output pressure of the otherelectric-hydraulic pressure control valve for the speed adjustmentcylinder and is calibrated to indicate feet per minute of hoist linespeed to enable the operator to set the speed control rheostataccordingly.

In testing a hoist rated at a particular load and speed, the operator atthe control station merely adjusts the load control and speed controlrheostats, so that the settings of the test winch match those of thehoist being tested. Thus, hoist-testing apparatus in accordance with theinvention eliminates the need to physically attach weights to or removethem from each hoist being tested. Furthermore, the apparatus is readilyadapted for use with hoists of different ratings by merely adjusting thespeed and load rheostat controls to set test winch speed and load todesired values. Brake tests requiring application of percent of ratedload to a stationary hoist line are carried out in the same way. Also,the apparatus employs commercially available hydraulic components (suchas pumps, motors, load cells, valves and the like) and is relativelyeconomical to fabricate and use. Furthermore, necessary load and speedadjustments are easily carried out by a single operator from a remotecontrol station.

These and other objects and advantages of the present invention willappear hereinafter as this disclosure progresses, reference being had tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS operation of the actuator shown inFIG. 2 and the valve shown in FIG. 3.

DESCRIPTION OF THE INVENTION Referring to FIG. 1 of the drawing, thenumeral 10 designates an electric hoist which is to be tested and ismounted on overhead rail 11. Hoist comprises a wheeled carriage 12 toadapt it for horizontal movement on rail 1 l and further comprises anelectric motor 14 energizable to rotate a hoist drum 15 to move a hoistline or cable 16 having a hook 17 in either direction vertically.Assume, for example, that hoist 10 is rated to handle a maximum load of(or has a line pull of) 50,000 pounds at a maximum speed of 150 feet perminute. Hoist 10 is disposed over a pit 18 in the floor of a structurein which testing is carried out. A control pendant 19 for controllingthe hoisting, lowering and braking functions of hoist 10 depends fromthe hoist.

Hoist test apparatus 20 and a control system therefor in accordance withthe invention is conveniently disposed in pit 18 for safety and spaceconsiderations and generally comprises a test winch 21 rigidly securedto the floor of the pit, means for connecting the test winch to hoist 10to apply predetermined loads thereto at predetermined speeds, means forproviding an indication of the load applied to hoist 10 by the testwinch, and means for operating and controlling the load imposed by andthe speed of the test winch.

Test winch 21 comprises a rotatable drum 22 (rotatable in the directionof an arrow 23 to wrap on cable) having a test cable 24 and a hydraulicmotor 26 operable to drive the drum through suitable gears 28. Hydraulicmotor 26, for example, is a conventional fixed volume piston-type motorrated at 3,000 p.s.i. and 13,000 ft.-lbs.

The means for connecting test winch 21 to hoist 10 comprises a lever 30,such as a steel beam, mounted for pivotal movement on a fulcrum 31rigidly secured to the floor of pit l8. Pulley means such as a sheave 32is removably connected to hook 17 of hoist 10. A sheave 33 is connectedto one end 34 of lever 30, and sheaves 35 and 36 are securely mounted atfixed positions in pit 18. Test cable 24 of winch 21 is reeved about thesheaves 36, 35, 33 and 32 and is also attached to sheave 33. Ashereinafter explained forces exerted between hoist line 16 and testcable 24 cause deflection or clockwise rotation (with respect to FIG. 1)of lever 30 and a predetermined amount of rotation corresponds to apredetermined amount of load or line pull imposed on hoist line 16.

The means for providing an indication of the load or line pull appliedto hoist line 16 of hoist 10 by test winch 21 comprises a conventionalhydraulic load cell 40 connected between the other end 41 of lever 30and a fixed point 42 in pit 18. Load cell 40 is connected by a pressureline 44 to a readout device or gauge 45 on an operators control panel 46located outside of pit 18. Load cell 40 translates the strain to whichit is subjected by clockwise pivotal movement of lever 30 into a visualreadout in pounds of load or line pull on gauge 45.

The means for operating test winch 22 comprises a hydraulic pump 50,such as a constant speed variable volume piston type pump, rated forexample ,at 3,000 p.s.i. and 45 G.P.M. and an electric motor 51 fordriving the pump, such as a conventional constant-speed squirrel cagetype motor rated, for example at 150 h.p. Pump 50 and electric motor 51are shown mounted on top of a hydraulic fluid reservoir 52 in pit 18.The fluid output from pump 50 is understood to be variable to change thespeed of hydraulic motor 26 of winch 21 by means of a reciprocablymovable servo-stem 53 provided thereon. A pump of this type designatedas a type PVC45-l0 variable in-line piston pump is shown in bulletinM-2222-S of the Vickers Division of Sperry Rand, Troy, Mich.

Pump 50 is provided with a fluid intake port 55 which is connected by ahydraulic fluid suction line 56 to the fluid in reservoir 52. Line 56 isprovided with a suction-type filter screen 57 for filteringfluidsupplied to pump 50. Pump 50 is also provided with a fluid outputor pressure port 60 which is connected by a hydraulic fluid line 61,containing a conventional check valve 64 to an inlet port 67 onhydraulic motor 26. Another port 74 of motor 26 is connected through afluid line 75, through a conventional spring-loaded check valve 70(rated for example to open at 3 p.s.i. pressure in line and through afluid line*71 and a filter 72 to the fluid in reservoir 52.

Another conventional spring-loaded check valve 76 (rated for example toopen at 50 p.s.i. suction in line 75) is connected to parallel with (butpoled opposite to) valve 70. Check valve 76 is used as a back pressurerelief check valve to keep 50 p.s.i. on the return side of hydraulicmotor 26 when the motor is running as a motor. This helps to eliminatepulsations of the hydraulic motor.

Means are provided to remotely control or regulate the speed ofhydraulic motor 26 of test winch 21 and comprises a spring loadedactuator 77 for reciprocably moving servo-stem 53 on pump 50. As FIGS. 1and 2 show, actuator 77 comprises a cylinder 78 having a piston 80 whichis provided with a pair of rods 82 and 84 extending from the ends 86 and88, respectively, of the cylinder. Rod 82 has a yoke 90 which isconnected to servo-stem 53 of pump 50. Rod 84 extends into a springhousing 92 at the end 88 of cylinder 78 in which a pair of movablewashers 94 and 96 and a centering spring 98 are also disposed. In FIGS.1 and 2, piston 80 and its associated rods 82 and 84 are shown inspringcentered position wherein servo-stem 53 is maintained in thezero-speed position and no fluid pressure is provided from port 60 ofpump 50 to hydraulic motor 26. In operation, as fluid pressure at port100 in cylinder 78 increases, it causes rightward movement (with respectto FIGS. 1 and 2) of piston 80 and the rods 82 and 84. As this occurs, ashoulder 102 on rod 84 bears against washer 94, thereby causingcompression of spring 98. When fluid pressure at port 100 decreases,spring .98 re-expands against washer 94 and moves rod 84 and piston 80back to their spring-centered positions shown in FIGS. 1 and 2. Actuator77 is designed, for example, so that 100 p.s.i. of fluid pressure isrequired to overcome the bias of spring 98 and initiate movement ofpiston 80 and an additional 100 p.s.i. of fluid pressure is required foreach quarter inch of rightward travel of the piston.

Referring to FIG. 1, fluid enters and leaves cylinder 78 of actuator 77through port 100 which is connected to a port 104 of a remotelycontrolled, electrically operated pressure control valve 106 of a knowntype which is shown in detail in FIG. 4. A fluid inlet port 108 of valve106 is connected by a hydraulic fluid line 110 to receive the fluidoutput of a constant volume, pressure compensated (constant pressure)pump 1 12 which is mounted on and driven by electric motor 51. Pump 112is supplied from reservoir 52 through a fluid line 114 having a filter116. Fluid port 108 of control valve 106 is connected by a fluid returnline 118 having a pressure relief valve 120 therein to reservoir 52.Pres sure control valve 106 comprises a valve body 122 on which a D.C.solenoid operating coil 124 is mounted. As FIG. 1 shows, one terminal126 of coil 124 is electrically connected by an electrical conductor 128to a terminal 130 of a D.C. power supply 132. The other terminal 134 ofcoil 124 is electrically connected by an electrical conductor 136 to thewiper 138 of a manually controlled potentiometer or rheostat 140 oncontrol panel 46. One end of the resistance element of potentiometer 140is electrically connected to the other terminal 142 of DC power supply132.

As FIG. 4 shows, control valve 106 comprises a spool valve having avalve spool 144 movable in a valve chamber 145 in valve body 122. Spool144 includes spaced collars 146 and 147 which cooperate with a flange148 to control the flow of fluid in and out of the inlet and outletports 104 and 108 which communicate with chamber 145. A variable orificeis formed by flange 148 and the collars 146 and 147 and the size of theorifice is altered by the positioning of valve spool 144 with respect tothe flange. The position of valve spool 144 is regulated by pilotpressure control means. Spool 144 is biased into the leftward positionshown in FIG. 4 (i.e. open position) by a spring 149. The pilot pressurecontrol means acts against the bias of spring 149 to control valve spoolposition. A pilot fluid line 150 in valve body 122 includes a controlport151 by which fluid pressure is applied to the valve spool. Thispressure tends to move valve spool 144 to the right against the force ofspring 149.

The pressure exerted on valve spool 144 by the fluid in control port 151is controlled by coil 124. A poppet valve 152 is interposed betweencontrol port 151 and a drain 153. A fluid passage 154 in valve spool 144connects control port 151 to poppet valve 152. Poppet valve 152 includesa poppet 155, a bias spring 156a, and apiston 156. Poppet 155 regulatesthe flow of fluid between control port 151 and drain 153 and thus, thepressure exerted on valve spool 144.

The position of poppet 155 is controlled by a relief valve 157interposed in fluid line 150 between control port 151 and drain 153. Thepoppet 158 of relief valve 157 is connected to the plunger 159 ofsolenoid coil 124. Relief valve 157 controls the fluid pressure appliedto piston 156 in accordance with its relief action which in turncontrols the position of poppet 155, the flow of fluid between controlport 151 and drain 153, the pressure exerted on valve spool 144 and,therefore, the position of the latter.

A speed control pressure gauge 250 is provided at control station 46 andis connected by a fluid line 252 to fluid pressure port 104 of pressurecontrol valve 106. Gauge 250 is responsive to the fluid output pressureof pressure control valve 106 and is calibrated to indicate feet perminute of hoist line speed. Gauge 250 enables the operator to set speedcontrol rheostat 140 at settings which establish predetermined linespeeds for hoist line 16. A predetermined pressure at pressure port 104of control valve 106 establishes a predetermined position for piston 80of actuator 77 and servostem 53 and thus, effects a predetermined speedof operation of winch motor 26.

Means are provided to remotely control, regulate, or limit the loadexerted on hoist 10 by hydraulicmotor 26 of test winch 21 and comprisesa conventional pilot operated, remotely adjustable pressure relief valve170. Relief valve 170 is remotely adjustable to regulate its pressurerelief setting to limit fluid flow to motor 26 by means of a remotelycontrolled, electrically operated pressure control valve 172,identicalin construction and operation to pressure control valve 106hereinbefore described. Relief valve 170 has an inlet port 174 which isconnected to fluid line 61 through a fluid line 175. Relief valve 170also has a normally closed pressure relief port 176 which is connectedthrough a hydraulic fluid line 177, through check valve 70, and throughfluid line 71 and filter 72 to reservoir 52.

As FIG. 3 shows, the pressure relief port 176 of valve 170 is normallyclosed off from communication with inlet port 174 by a movable spool 178which is biased to closed position by a compression spring 180 in thehousing of valve 170 and by fluid pressure in a chamber 182 behind spool178. Chamber 182 is connected to inlet port 174 tluough a fluidpassageway 184 in spool 178 and the fluid therein is normally at thesame pressure as the fluid at port 174. When fluid pressure in chamber182 reaches a predetermined level, a normally closed poppet valve 186 isforced open against the bias of a spring 188 to allow communicationbetween chamber 182 and outlet port 176 through a passageway 190 in thevalve housing and a passageway 192 in spool 178. Poppet valve 186 isbiased closed by the force of a spring 194 which is acted upon by amovable plunger or piston 196. The amount of mechanical pressure exertedby plunger 196 against spring 194 determines the pressure level at whichpoppet 186 unseats, and therefore, the pressure level at which spool 178moves to open position. The force on plunger 196, in turn, is a functionof the fluid pressure exerted thereagainst from an outlet port 200 ofpressure control valve 172 through a fluid line 202. A fluid inlet port204 of control valve 172 is connected to fluid line to receivepressurized fluid from pump 112. A solenoid operating coil 206 of valve172 has one terminal 208 electrically connected by an electricalconductor 210 to terminal of power supply 132. The other terminal 212 ofcoil 206 is electrically connected by an electricalconductor 214 to thewiper 216 of a manually controlled potentiometer or rheostat 218 oncontrol panel 46. The resistance element of potentiometer 218 iselectrically connected to the other terminal 142 of power supply 132.

A load control pressure gauge 254 is provided at control station 46 andis connected by a fluid line 256 to fluid pressure port 200 of pressurecontrol valve 172. Gauge 254 is responsive to the fluid output pressureof pressure control valve 172 and is calibrated to indicate pounds ofline pull or load which hoist line 16 can exert. Gauge 254 enables theoperator to set load control rheostat 218 at settings which establishpredetermined loads for hoist line 16. A predetermined pressure atpressure port 200 of control valve 172 establishes a predeterminedpressure at which pressure relief valve will open. I

Operation of the invention is as follows. Assume that hoist 10,connected as shown in FIG. 1 is to be tested and that itis rated, forexample, to have a maximum load or line pull of 25,000 pounds at 200feet per minute. In carrying out all tests, as hereinafter described,assume that electric motor 51 and pump 50 are in operation. Also assumethat the operator at control station 46 is able to control the raising,lowering and braking function of hoist 10 by means of control pendant19. Further assume that speed control means and load control means havebeen set (or are adjusted during the tests) by the operator by means ofthe rheostats 140 and 218, respectively, on panel 46 for the specifiedrating of hoist 10. Finally, assume that hoist 10 is to undergo fourtests as follows:

Test 1. Hoist is braked so that its drum is stationary and maximum ratedload is to be imposed thereon.

Test 2. Hoist is braked so that its drum is stationary and 150 percentof maximum rated load is to be imposed thereon.

Test 3. Hoist operating in the hoist direction and maximum rated load isto be imposed thereon.

Test 4. Hoist operating in the lower direction and maximum rated load isto be imposed thereon.

During Test No. l, which is a static load test, hydraulic motor 26 issupplied with fluid from port 60 of pump 50 through line 61,'check valve64, and port 67. Therefore, motor 26 operates as a motor and rotates (ortends to rotate) winch drum. 22 in the direction of arrow 23 so thattest cable 24, acting through the pulleys and lever 30 exerts a downwardpulling force or strain on hoist line 16 (which remains stationarybecause it is braked). The force increases until it equals the ratedload of hoist 10, at which point pressure relief valve 170 opens toprevent motor 26 from exerting any greater force. However, motor 26continues to maintain this degree of force on hoist line 16.Simultaneously, lever 30 is deflected or pivoted very slightly in theclockwise direction (with respect to FIG. 1) thereby imposing a strainon load cell 40 equal (or proportional) to that imposed on hoist line 16and this is registered on gauge 45 on panel 46 in pounds of load or linepull.

During Test No. 2, which is also a static load test, assume thatconditions are the same as in Test No. 1 (i.e., the hoist brake is setand hoist line 16 is stationary) but it is desired to impose 150 percentof rated load on hoist 10 to test the hoist brakes. Normally, the hoistbrake is set under maximum rated load conditions and then checked at 150percent of this value. To accomrequires more fluid, such is availablefrom reservoir 52 through filter 72, line 71, check valve 70, line 75and port 74 of motor 26. During test No. 3, lever 30 is deflected orpivoted clockwise (with respect to the drawing) in responseto thepulling action of hoist 10 and load cell 40 senses this to provide areadout on gauge 45.

During test No. 4, which is a running load test, hoist 10 is operatingin the lowering direction and hoist line 16 is descending at ratedspeed. Consequently, test cable 24 is wrapped on test winch drum 22 asthe latter is rotated in the direction of arrow 23. Under theseconditions, hydraulic motor 26 runs as a motor but must run atsufficient speed and with sufficient torque to keep up with the speed ofhoist 10 and still impose maximum load thereon. In the course of testNo. 4, then, test cable 24 still causes clockwise deflection or pivoting(with respect to the drawing) of lever 30 and load cell 40 provides anappropriate reading on gauge 45.

In regard to tests Nos. 3 and 4, it should be noted that the runningline pull of electric hoist 10 going up is different from the runningline pull going down. This is due to the fact that its planetary gearsrun at a different efficiency going up than when going down. Old testmethods used weights and more weights would be used going up and lessweights going down. In accordance with the invention, the operator canset the proper load going up and doing down with load potentiometer 218.

Correct load is sensed by load cell 40 and shown at gauge 45.

It is to be understood that, if a hoist to be tested exceeds theload-handling capacity of hydraulic motor 26 and pump 50 shown,additional motors and pumps could readily be connected in paralleltherewith to increase tl'ie capacity of test apparatus 20.

plish this, the operator at control panel 46 adjusts load control 218 toincrease the pressure setting for pressure relief valve 170 to thedesired pressure, i.e., 150 percent of rated load. Thus, hydraulic motor26 is able to operate as a motor and exert this greater degree of strainon hoist line 16 before pressure relief valve 170 opens. Thus test No. 2may be carried out subsequent to test No. l merely making one controladjustment.

During Test No. 3, which is a running load test, hoist 10 is operatingin the hoist direction and hoist line 16 is ascending at rated speed.Consequently, test cable 24 is unwrapping from test winch drum 22 andtoaccomplish this, drum 22 mustrotate in a direction opposite to arrow 23.Under this condition, hydraulic motor 26 runs in reverse or acts as apump but it is pumping against pressurized fluid being supplied frompump 50 to motor port 67. Therefore, this resistive force acts tomaintain the maximum load on hoist cable 16. If operation of motor 26 asa pump reaches the point where it Furthermore, test apparatus inaccordance with this invention need not be confined to a pit as shown,but could be installed or applied in other ways.

Finally, the pulley means associated with lever 30 could take otherforms, depending on the mechanical advantage desired, and load cell 40could be connected to lever 30 in some other manner, provided it givesan appropriate load indication.

I claim:

1. Apparatus for testing a hoist having a hoist line and rated to have apredetermined line pull and predetermined line speed comprising;

a test winch,

connecting means for connecting the hoist line to said test winch, saidconnecting means including a member movable in proportion to the amountof line pull or load imposed on said hoist by said test winch,

sensing means responsive to the movement of said member and providing anindication of the size of load being imposed,

load control means for controlling the size of the load imposed by saidtest winch on said hoist, and

speed control means for controlling the speed of said test winch so thatit is related to hoistline speed.

2. Apparatus according to claim 1 wherein said test I winch comprises ahydraulic motor driven by a hydraulic pump, wherein said load controlmeans controls said motor, and wherein said speed control means controlssaid pump.

3. Apparatus according to claim 2 wherein said load control meanscomprises a pressure relief valve connected between said pump and saidmotor and wherein said speed control means comprises speed adjustmentmeans on said pump.

4. Apparatus according to claim 3 wherein said sensing means provides anindication of load size at a control station and wherein said pressurerelief valve and said speed adjustment means are remotely adjustablefrom said control station.

5. Apparatus according to claim 4 including a hydraulic fluid reservoirfor supplying said pump, a hydraulic fluid line connected between saidreservoir and said motor and between said reservoir and said re liefvalve, and first and second check valves in parallel but in oppositerelationship with each other in said line, said first check valvepermitting fluid flow to said motor when the latter is acting as a pump,said second check valve permitting fluid flow to said reservoir fromsaid relief valve when said relief valve exceeds its pressure setting.

6. Apparatus according to claim 5 wherein said sensing means comprises aload cell connected to said movable member.

7. Apparatus according to claim 6 wherein said test winch comprises atest cable, wherein said connecting means comprises a lever as saidmovable member and wherein said connecting means further comprisespulley means connected to said lever, said hoist line and said testcable being connected to said pulley means.

8. Apparatus according to claim 7 wherein said pulley means areconnected to said lever on one side of said fulcrum and said sensingmeans comprises a load cell which is connected to said lever on theother side of said fulcrum.

9. Apparatus according to claim 4 wherein said load control meanscomprises a first electric-hydraulic pressure control valve remotelyoperable from said control station to adjust said pressure relief valve,and wherein said speed control means comprises a secondelectrichydraulic pressure control valve remotely operable from saidcontrol station and a hydraulic actuator controlled thereby to adjustsaid speed adjustment means on said pump.

10. Apparatus according to claim 9 wherein said first and secondelectric-hydraulic pressure control valves are remotely operable byrheostats at said control station.

11. Apparatus according to claim 9 wherein said load control meanscomprises load indicator means at said control station responsive tofluid pressure supplied by said first electric-hydraulic pressurecontrol valve to said pressure relief valve to indicate a load settingfor said hoist, and wherein said speed control means comprises speedindicator means at said control station responsive to fluid pressuresupplied by said second electric-hydraulic pressure control valve tosaid actuator to indicate a speed setting for said hoist.

12. Apparatus according to claim 11 wherein said load indicator meansprovides a readout in pounds and wherein said speed indicator meansprovides a readout in feet per minute.

13. Apparatus according to claim 10 wherein said rheostats establishpressure levels at the pressure ports of said pressure control valves.

1. Apparatus for testing a hoist having a hoist line and rated to have apredetermined line pull and predetermined line speed comprising; a testwinch, connecting means for connecting the hoist line to said testwinch, said connecting means including a member movable in proportion tothe amount of line pull or load imposed on said hoist by said testwinch, sensing means responsive to the movement of said member andproviding an indication of the size of load being imposed, load controlmeans for controlling the size of the load imposed by said test winch onsaid hoist, and speed control means for controlling the speed of saidtest winch so that it is related to hoist line speed.
 2. Apparatusaccording to claim 1 wherein said test winch comprises a hydraulic motordriven by a hydraulic pump, wherein said load control means controlssaid motor, and wherein said speed control means controls said pump. 3.Apparatus according to claim 2 wherein said load control means comprisesa pressure relief valve connected between said pump and said motor andwherein said speed control means comprises speed adjustment means onsaid pump.
 4. Apparatus according to claim 3 wherein said sensing meansprovides an indication of load size at a control station and whereinsaid pressure relief valve and said speed adjustment means are remotelyadjustable from said control station.
 5. Apparatus according to claim 4including a hydraulic fluid reservoir for supplying said pump, ahydraulic fluid line connected between said reservoir and said motor andbetween said reservoir and said relief valve, and first and second checkvalves in parallel but in opposite relationship with each other in saidline, said first check valve permitting fluid flow to said motor whenthe latter is acting as a pump, said second check valve permitting fluidflow to said reservoir from said relief valve when said relief valveexceeds its pressure setting.
 6. Apparatus according to claim 5 whereinsaid sensing means comprises a load cell connected to said movablemember.
 7. Apparatus according to claim 6 wherein said test winchcomprises a test cable, wherein said connecting means comprises a leveras said movable member and wherein said connecting means furthercomprises pulley means connected to said lever, said hoist line and saidtest cable being connected to said pulley means.
 8. Apparatus accordingto claim 7 wherein said pulley means are connected to said lever on oneside of said fulcrum and said sensing means comprises a load cell whichis connected to said lever on the other side of said fulcrum. 9.Apparatus according to claim 4 wherein said load control means comprisesa first electric-hydraulic pressure control valve remotely operable fromsaid control station to adjust said pressure relief valve, and whereinsaid speed control means comprises a second electric-hydraulic pressurecontrol valve remotely operable from said control station and ahydraulic actuator controlled thereby to adjust said speed adjustmentmeans on said pump.
 10. Apparatus according to claim 9 wherein saidfirst and second electric-hydraulic pressure control valves are remotelyoperable by rheostats at said control station.
 11. Apparatus accordingto claim 9 wherein said load control means comprises load indicatormeans at said control station responsive to fluid pressure supplied bysaid first electric-hydraulic pressure control valve to said pressurerelief valve to indicate a load setting for said hoist, and wherein saidspeed control means comprises speed indicator means at said controlstation responsive to fluid pressure supplied by said secondelectric-hydraulic pressure control valve to said actuator to indicate aspeed setting for said hoist.
 12. Apparatus according to claim 11wherein said load indicator means provides a readout in pounds andwherein said speed indicator means provides a readout in feet perminute.
 13. Apparatus according to claim 10 wherein said rheostatsestablish pressure levels at the pressure ports of said pressure controlvalves.